In a colonoscopy, a bowel lavage medicine is used for preparative treatment. Such a preparative medicine should be in the form of an aqueous solution for allowing it to be taken by mouth. However, under the aqueous solution, the medicine is subjected to degeneration or coloring with time. Therefore, in an actual shape of product, the medicine of a powder state is tightly stored in a four side seal bag or a self-support bag functioning also as a container for solving the medicine to obtain its solution, which bag is made from soft films. It is, therefore, usual that the bag is opened just before the use and an aqueous solution is obtained for the instant use. See, for example, patent document 1 as far as a container of a soft bag type is concerned, where an application of water is done for obtaining the aqueous solution when used.
In such bowel lavage medicine, which is essentially under a powder state and is solved by water just before the use, a type that includes, in combination, polyethylene glycol (PEG) and electrolyte has conventionally been known. In this type, a large quantity of, at the most, as much as 4 liter is needed, which is highly non-desirable for a people of reduced physical strength, such as an aged person. In view of this, a type of bowel lavage medicine for realizing a reduced quantity of medicine has recently been proposed, in which ascorbic acid (vitamin C) is added to the polyethylene glycol (see patent document 2). This ascorbic acid added type is improved in its bowel lavage ability, so that a reduction of a quantity of medicine to a value between 1 and 2 liter is realized over the large quantity in the prior art of, at the maximum, as much as 4 liter. In short, the ascorbic acid added type is advantageous since a reduction of physical strain is obtained for those who take medicine.    PATENT DOCUMENT 1: Japanese Un-Examined Patent Publication No. 11-285518    PATENT DOCUMENT 2: Publication of Japanese Patent No. 4131266